1. Field of the Invention
The present invention relates to a shaking sensing unit, an apparatus for correcting shaking comprising the shaking sensing unit, and a method of correcting shaking, and more particularly, to a shaking sensing unit which can accurately correct shaking occurring due to hand shaking of a user in a photographing device such as a still camera or a video camera, an apparatus for correcting shaking comprising the shaking sensing unit, and a method of correcting shaking.
2. Description of the Related Art
When a photographing device is shaken due to hand shaking by a user during photography, images are not clearly photographed. A shaking correction apparatus can correct the shaking of the photographing device, and thus clear images can be obtained.
Conventional shaking correction apparatuses adopt either a method of optically correcting shaking or a method of correcting shaking using software. The optical correction method is divided into a method of correcting an image by moving lenses to offset the shaking of the photographing device and a method of correcting by moving an image sensor to offset the shaking of the photographing device.
In the software correction method, images are processed using software. For example, in a shaking correction mode, an image is photographed several times for a predetermined time and only an image with the least motion blur is processed and stored, or an image is photographed several times, brightness information and image information are respectively extracted, and an image with the least motion blur is stored.
However, in a photographing device adopting the shaking correction method, particularly, the optical correction method, only shaking having a frequency range between 4-15 Hz is set to be corrected due to a technical limit in extending a shaking correction range. Thus, it is difficult to correct shaking having a frequency outside the range of 4-15 Hz.
In detail, when the photographing device is fixed on a tripod or any other similar device (a mechanism for fixing a photographing device), the shaking correction apparatus in a shaking correction mode keeps a lens located at the center thereof during the photography. However, since a tripod is usually made of a highly rigid material such as aluminum, the tripod is not able to absorb an external impact or vibration, and rather it transfers or amplifies the external impact or vibration. In the meantime, it is known that the frequency of hand shaking of a user holding the photographing device is generally 4-15 Hz.
Thus, when the photographing device is fixed on a tripod or the photographer is transported in a vehicle, the external impact or vibration delivered to the photographing device, that is, fine shaking due to the shaking of the tripod itself or excessive vibration due to the vehicle, may be lower than 4 Hz or higher than 15 Hz, that is, outside the range of frequency of the hand shaking. In this case, when an image is photographed using a conventional photographing device in the shaking correction mode, a shaking sensing sensor included in the photographing device senses the impact and vibration and reacts thereto. However, the reaction, that is, correction, by the shaking sensing sensor is performed outside the frequency range of natural human shaking so that a mistake in correction, for example, over-correction is performed. As a result, the mistake in correction produces a more unclear image. That is, since the shaking correction apparatus overreacts to the fine shaking transferred to the photographing device, it is difficult to obtain a clearer image than in a normal mode that is not the shaking correction mode.